OpenID is a shared identity service, which allows Internet users to log on to many different web sites using a single digital identity, eliminating the need for a different user's name and password for each web site. OpenID is a decentralized, free and open standard that is distributed across the Internet and maintained by numerous organizations, including major sites, such as AOL™ and Yahoo!™.
In an OpenID system, a user, commonly referred to as an “OpenID user,” transmits an authorization request or a logon request to a web site the user wants to log on. The authorization request may include what is referred to as an “OpenID identifier.” A web site that accepts OpenID is known as the “relying party,” because it relies upon an “identity provider” for authentication. As stated above, the web site may receive an OpenID identifier from the OpenID user. The OpenID identifier may be a Uniform Resource Locator (“URL”) of the identity provider with a username appended to it or it may be Extensible Resource Identifier (“XRI”) i-name. I-names are human-friendly names, such as “John.doe,” that are linked to the OpenID provider.
When an OpenID user logs into an OpenID web site, the script in the web page redirects the browser of the OpenID user to the identity provider identified in the OpenID identifier. Using a password or other method, the identity provider attempts to authenticate the user and informs the relying party of its success or failure.
However, if the identity provider is unavailable, then the OpenID user cannot be authenticated and hence cannot access the OpenID web site. That is, when the identity provider is unavailable, the OpenID web site will not be able to leverage the security authentication functionality of the requested identity provider. As a result, the OpenID user will not be authenticated and will not be able to access the OpenID web site.